1. Field
The present disclosure relates generally to cementitious materials, and more particularly, relates to a low density extruded monolithic cementitious shaped article and methods of manufacturing the same.
2. Description of the Related Art
Fiber cement materials are commonly used in building construction. Fiber cement boards, for example, can be used both in the interior of a house, such as for tile backing, and on the exterior of the house, such as for siding. Efforts have been made to develop various low cost methods to reduce the density and weight of fiber cement while maintaining desirable performance characteristics of the material. For example, low density fillers, such as ceramic microspheres, have been incorporated in fiber cement products to reduce the weight and material cost. The fillers are generally selected to reduce the density of the fiber cement without substantially impairing the performance characteristics of the final product in both installation and lifetime durability and performance.
It is, however, particularly challenging to incorporate low density fillers into fiber cement building products formed by extrusion. Low density fillers have difficulty withstanding the physical and mechanical forces imparted by the extrusion process, which is commonly used for manufacturing cellulose fibers reinforced cement sheets and panels. Like air voids, the fillers can burst or be crushed under the high pressure and temperature conditions encountered during the extrusion process. As such, it is very difficult to control the distribution or amount of low density fillers in monolithic, extruded fiber cement materials.